Weiss G A, Valentekovich R J, Collins E J, Garboczi D N, Lane W S, Schreiber S L, Wiley D C
Department of Chemistry, Harvard University, Cambridge, MA 02138, USA.
Proc Natl Acad Sci U S A. 1996 Oct 1;93(20):10945-8. doi: 10.1073/pnas.93.20.10945.
The class I major histocompatibility complex (MHC) glycoprotein HLA-B27 binds short peptides containing arginine at peptide position 2 (P2). The HLA-B27/peptide complex is recognized by T cells both as part of the development of the repertoire of T cells in the cellular immune system and during activation of cytotoxic T cells. Based on the three-dimensional structure of HLA-B27, we have synthesized a ligand with an aziridine-containing side chain designed to mimic arginine and to bind covalently in the arginine-specific P2 pocket of HLA-B27. Using tryptic digestion followed by mass spectrometry and amino acid sequencing, the aziridine-containing ligand is shown to alkylate specifically cysteine 67 of HLA-B27. Neither free cysteine in solution nor an exposed cysteine on a class II MHC molecule can be alkylated, showing that specific recognition between the anchor side-chain pocket of an MHC class I protein and the designed ligand (propinquity) is necessary to induce the selective covalent reaction with the MHC class I molecule.
I类主要组织相容性复合体（MHC）糖蛋白HLA - B27结合在肽段第2位（P2）含精氨酸的短肽。HLA - B27/肽复合物在细胞免疫系统中T细胞库的发育过程以及细胞毒性T细胞激活过程中均被T细胞识别。基于HLA - B27的三维结构，我们合成了一种含氮丙啶侧链的配体，该侧链旨在模拟精氨酸并共价结合于HLA - B27的精氨酸特异性P2口袋。通过胰蛋白酶消化，随后进行质谱分析和氨基酸测序，结果表明含氮丙啶的配体特异性烷基化了HLA - B27的半胱氨酸67。溶液中的游离半胱氨酸或II类MHC分子上暴露的半胱氨酸均未被烷基化，这表明MHC I类蛋白的锚定侧链口袋与设计配体之间的特异性识别（邻近性）对于诱导与MHC I类分子的选择性共价反应是必要的。
